I. Field of the Invention
The present invention provides a method for determining the amount of open sky view of an antenna in an automotive vehicle.
II. Description of Material Art
Satellite radio receivers as well as GPS receivers are becoming increasingly popular for use with automotive vehicles. Satellite radio as well as GPS radio signals are transmitted from their respective satellite at very high frequencies, i.e. frequencies in excess of 1 gigahertz. Such high frequency radio waves are received only on a line of sight basis so that an obstruction which is non-transmissive of electromagnetic waves, e.g. metal objects, between the transmitter and the receiver will preclude reception of the radio transmission by the receiver.
Consequently, in order to ensure clear radio reception as well as reception from the number of GPS satellites necessary to render the GPS system operational, it is desirable that the antenna for the satellite radio and GPS system have as much as an open sky view as is possible.
One method of maximizing the amount of open sky view for the automotive vehicle is to place the automotive antenna on the car top. This solution, however, is not wholly desirable in that it exposes the antenna to the environment which can damage the antenna and also to vehicle washing equipment which can also damage the antenna. Indeed, in extreme cases, the attachment between the antenna and the vehicle roof or back deck may become damaged and result in water seepage into the passenger compartment. Additionally, many customers object to the appearance of a roof mounted antenna and prefer a hidden antenna.
In order to avoid the problems associated with roof-mounted antennas, many vehicles mount the antenna for satellite radio and GPS radio transmissions under or on the vehicle instrument panel so that the antenna is at least partially open to the sky through the vehicle windshield. However, by placing the antenna on the inside of the vehicle, there are certain objects positioned in between the antenna and the satellite that are constructed of materials that are non-transmissive to electromagnetic radiation, e.g. metal objects. Such objects include, for example, the vehicle front pillars, portions of the rearview mirror, etc.
Consequently, in order to determine the amount of open sky view for the antenna, it has been previously necessary to create a computer simulation of the objects of the vehicle that are non-transmissive to electromagnetic radiation. Thereafter, a number of sections are taken through the simulation and the area obscured by these non-transmissive objects determined for the various sections and then subsequently summed to a total. That total is then compared with the total sky area to determine the percentage of the sky view that is open to the antenna. If the amount of open sky view is less than a designated amount, e.g. 83%, the position of the antenna is moved and the above process is repeated.
A primary disadvantage of these previously known methods to determine the amount of open sky view is disadvantageously time consuming and tedious. Furthermore, since the amount of open sky view is determined manually, the process was subject to potential human error.